Image forming apparatus

Abstract

In an image forming apparatus, an image forming condition is changed depending on whether or not a recording material on which a toner image is formed is ordinary high gloss paper or thermoplastic resin coated paper. More specifically, in the case where a high gloss mode is selected during image formation, judgement whether or not the high gloss paper is the ordinary high gloss paper or the thermoplastic resin coated paper is made. In the former case, a screen line number is set to 150 lpi, and in the latter case, the screen line number is set to 200 lpi. As a result, image failure due to collapse of a toner layer (during fixation) on the ordinary high gloss paper is prevented and high-quality toner image is formed on the thermoplastic resin coated paper.

1. An image forming apparatus, comprising:
 an image formation device configured and positioned to form a toner image on a recording material; 
 a first image heating device configured and positioned to heat the toner image on the recording material; 
 a second image heating device, disposed at downstream side of said first image heating device in a conveying direction of the recording material, configured to heat the toner image on the recording material heated by said first image heating device; 
 a selecting device configured and positioned to select one of high gloss modes including a first high gloss mode for performing image heating process only by said first image heating device and a second high gloss mode for performing image heating process by said first image heating device and said second image heating device; and 
 a controlling device configured and positioned to control an image forming condition of said image formation device so that a maximum amount of toner per unit area in the first high gloss mode is smaller than that in the second high gloss mode. 
 
   
   
     2. An apparatus according to  claim 1 , wherein a temperature that the recording material is separated from said first image heating device is higher than a temperature that the recording material is separated from said second image heating device. 
   
   
     3. An apparatus according to  claim 1 , wherein said second image heating device comprises
 a belt, disposed on a side where it contacts the toner image on the recording material, which heats the toner image on the recording material, 
 a nip forming member, which forms a nip with said belt cooperatively, and 
 a cooling device which cools the recording material, before separation, placed in a state of contact with said belt. 
 
   
   
     4. An apparatus according to  claim 1 , wherein when a recording material provided at its surface with a resin coated layer having a characteristic that the layer is softened by heat from said second image heating device is used, said selecting device selects the second high gloss mode. 
   
   
     5. An image forming apparatus, comprising:
 an image formation device configured and positioned to form a toner image on a recording material; 
 a first image heating device configured and positioned to heat the toner image on the recording material; and 
 a second image heating device, disposed at downstream side of said first image heating device in a conveying direction of the recording material, configured to heat the toner image on the recording material heated by said first image heating device; 
 a selecting device configured and positioned to select one of high gloss modes including a first high gloss mode for performing an image heating process only by said first image heating device and a second high gloss mode for performing an image heating process by said first image heating device and said second image heating device; and 
 a controlling device configured and positioned to control an image forming condition of said image forming device so that a screen line number in the first high gloss mode is smaller than that in the second high gloss mode. 
 
   
   
     6. An apparatus according to  claim 5 , wherein a temperature that the recording material is separated from said first image heating device is higher than a temperature that the recording material is separated from said second image heating device. 
   
   
     7. An apparatus according to  claim 5 , wherein said second image heating device further comprising:
 a belt, disposed on a side where it contacts the toner image on the recording material, which heats the toner image on the recording material; 
 a nip forming member, which forms a nip with said belt cooperatively; and 
 a cooling device which cools the recording material, before separation, placed in a state of contact with said belt. 
 
   
   
     8. An apparatus according to  claim 5 , wherein when a recording material provided at its surface with a resin coated layer having a characteristic that the layer is softened by heat from said second image heating device is used, said selecting device selects the second high gloss mode.